Means for opening hermetically-sealed casings



Jan. 1, 1957 F. LOWITZ MEANS FOR opzumc HERMEITICALLY-SEALED CASINGSFiled May 17, 1954 4 Sheets-Sheet l Jan. 1, 1957 F. ow1'rz MEANS FOROPENING HERMETICALLY-SEALED CASINGS 4 Sheets-Sheet 2 Filed May 17, 1954Jan. 1, 1957 F. LOWlTZ MEANS FOR OPENING HERMEITICALLY-SEALED CASINGS 4Shets-Sheet 3 Filed May 17, 1954 .m a 4 e 5 2 A! O 3 o L m b w 6 a m 9 XJ 1 N V EN TOR.

Fawn A Oh 72 Jan. 1, 1957 F. LOWITZ MEANS FOR OPENINGHEIRMETICALLY-SEALED CASINGS Filed May 17, 1954 4 Sheets-Sheet 4INVENTOR.

3 w Elli a a ummmmnifimmmmm Arm/vex United States Patent NIEANS FOROPENING HERMETICALLY-SEALED CASIN GS Frank Lowitz, Bronx, N. Y.

Application May 17, 1954, Serial No. 430,242

14 Claims. (Cl. 51-105) This invention relates to a means for openinghermetically sealed casings.

At the present time, it is the practice in many fields, and particularlyin the fields of refrigeration and airconditioning, to provide aso-called sealed unit which includes an electric motor and a compressorhoused within a casing. The casing consists of two parts which areinterfitted and welded together along a circular or oval seam. Electricleads and gas lines extend to the motor and compressor through openingsin the casing. If any trouble develops in the motor or compressor theentire unit is considered to be defective and is replaced. Usually adefective unit is discarded as worthless because equipment is notreadily available for opening up the casing so as to obtain access tothe motor and/or compressor for repair. Even when the equipment, a latheor even a heavy hand grinder, is available, it takes a man so long toopen up a unit that, taking into consideration the fact that the motoror compressor may be beyond repair, it is rare that a unit is salvaged.

It is an object of the present invention to provide an apparatus foropening hermetically sealed units.

More specifically it is an object of my invention to provide anapparatus which is particularly designed to open the welded seams oftwo-part hermetically sealed casings of the type commonly employed tohouse refrigeration motors and compressors.

It is another object of my invention to provide an apparatus of thecharacter described which do not require constant attendance, i. e., aresemi-automatic in operation, so that while the apparatus is opening oneunit, the operator can work on previously opened units.

It is another object of my invention to provide an apparatus of thecharacter described the controls of which are so simplified that it canbe operated by comparatively unskilled labor.

It is another object of my invention to provide an apparatus of thecharacter described which is adapted to open sealed units of variousshapes, size and types.

It is another object of my invention to provide an apparatus of thecharacter described the construction of which is relatively inexpensiveand simple.

It is another object of my invention to provide an apparatus of thecharacter described which is fast and durable in operation and highlyefficient in use.

Other objects of my invent-ion in part will be obvious and in part willbe pointed out hereinafter.

My invention accordingly consists in the features of construction,combinations of elements and arrangement of parts which will beexemplified in the device hereinafter described and of which the scopeof application will be indicated in the appended claims.

In the accompanying drawings in which is shown one of the variouspossible embodiments of my invention,

Fig. 1 is a side view of a machine constructed in accordance with myinvention set up to operate on a sealed unit having a lateral partingseam;

Fig. 2 is a top view thereof;

Patented Jan. 1, 1957 Fig. 3 is a sectional view taken substantiallyalong the line 3-3 of Fig. 2 and illustrating the work holder andgrinding head in operative association;

Fig. 4 is an enlarged sectional view taken substantially along the line4-4 of Fig. 3 and illustrating a detail of the adjustable clamp whichforms part of the centering jig;

Fig. 5 is an enlarged sectional view taken substantially along the line5-5 of Fig. 3 and illustrating another detail of said clamp;

Fig. 6 is an enlarged sectional view taken substantially along the line6-6 of Fig. l and illustrating a detail of the support for the grindingwheel motor;

Fig. 7 is a sectional view taken substantially along the line 7-7 ofFig. 2 and illustrating a detail of the adjustment which permitsposition of the axis of revolution of the grinding wheel to be varied;

Fig. 8 is a sectional view taken substantially along the line 8-8 ofFig. 2 and illustrating further details of the support for the grindingwheel motor;

Fig. 9 is a sectional view taken substantially along the line 9-9 ofFig. 8 and illustrating the mechanism for guiding the grinding wheel ina fixed horizontal plane when set up to rotate about a vertical axis;

Fig. 10 is a plan view of one of the clamping jaws of the centering jig;

Fig. 11 is a view similar to view 2, but illustrating the machine set upto operate on a sealed unit having a top parting seam;

Fig. 12 is an end view of the grinder and two-part casing shown in Fig.11; and

Fig. 13 is a sectional view taken substantially along the line 13-13 ofFig. 11 and illustrating the mechanism for guiding the grinding wheel ina fixed vertical plane when set up to turn about a horizontal axis.

In general, I carry out the several objects of my invent-ion byproviding a machine including a grinding wheel which is mounted toselectively rotate about either a vertical axis or a horizontal axis,and which when mounted to rotate about a vertical axis is shiftableinwardly toward the unit being opened and when mounted to rotate about ahorizontal axis is shiftable downwardly against the unit being opened.

The machine further includes a work holding table which is power drivenabout a horizontal axis whereby to present successive portions of theparting seam to the grinding wheel. Furthermore, the table hasincorporated therein a centering jig that automatically locates thecenter of sealed units of all sizes and shapes over the center of thetable.

Referring now in detail to the drawings, and more particularly to Figs.1 through 10, the reference numeral 20 denotes a machine constructed inaccordance with my invention. Said machine basically includes twointegrated mechanisms, to wit, a grinding head 22 and a work holder 24.

The machine is adapted to operate upon a sealed unit such as the unit 26illustrated in Fig. 1. This unit constitutes a casing that includes twointerfitted parts, i. e., a lower part 28 and an upper part 30. Theadjoining portions of the two parts have outwardly extending flangeswhose peripheries are abutted along a lateral parting seam that isclosed by a weld joint 32. It is this joint which must be removed inorder to separate the two parts of the casing and gain access to themotor and compressor. Inasmuch as the joint connects lateral flanges ofthe two parts of the casing the joint faces radially outwardly and bestcan be ground off by a grinding wheel whose perimeter lies in the planeof the joint.

Another common type of sealed casing 34 on which the machine is adaptedto operate is shown in Figs. 11 and 12. This casing consists of twoparts, to wit, a deep cup 36 and a cover 38 received in the mouth of thecup. The rims of the cup and cover are substantially coplanar at the topof the casing and are connected by a welded joint 40 which facesupwardly. Hence this joint best can be removed by a grinding wheel whoseperimeter is perpendicular to the plane of the joint.

Inasmuch as it is desired to minimize the number of unit-openingmachines employed in a shop the machine 20 must be suflicientlyversatile to handle both of these two basic types of casings justmentioned. In describing said machine, it first will be considered (andillustrated in Figs. 11()) as set up to handle a casing such as thecasing 26 for which the grinding wheel should rotate about a verticalaxis. Thereafter, the set-up will be described for operation on a casingsuch as the casing 34, for which the grinding wheel should rotate abouta horizontal axis.

The Work holder 24 includes a stationary hollow upright column 42 (Figs.1 and 3) in which a vertical shaft 44 is disposed. The bottom of theshaft rests on a step bearing 46 and the shaft is journalled near itsupper end in a line bearing 48 carried by the column. The top of theshaft projects above the column for securement to a horizontal table 50which conveniently is in the shape of a Greek cross (see Fig. 2)constituting a hub 52 and four radially extending arms 54.

Said table is provided with a work holding clamp including a centeringjig which automatically positions any unit to be opened with its centerdirectly above the center of the shaft 44.

For this purpose each of the arms 54 is formed with a longitudinal slot56 in which an H-shaped shoe 58 (see Fig. 5) is slidable. The shoecarries upper and lower plates 60 which rub against the upper and lowersurfaces of the arms 54.

In the openings 62 formed between the sides of the slot 56 and thecrossbar and legs of the H, vertical standards 64 are adjustablyreceived. Each shoe 58 has associated therewith two standards which areheld in position by a pin 66 (see Fig. 4) whose outer ends are receivedin selected openings 68 of a vertical series of such openings providedin the standards. The pin also passes through a block 70 that is securedto the upper plates 60 and lies between the openings 62. It will beappreciated that the openings 68 selected will depend upon the heightdesired for the standards.

The upper ends of the standards are provided with journals 72 thatreceive registered horizontal stub shafts '74 extending outwardly from aclamp block 76. The position of the block is angularly fixed withrespect to the axis of the shafts 74 by set screws 78 in the standards64. The clamp block is pierced to receive a clamp shaft 80 that extendsinwardly radially of the table 50. The inner end of the clamp shaftcarries a V-shaped clamping jaw 82 (Fig. 10) which is designed to bearagainst the exterior surface of the casing of a hermetically sealedunit. The jaw 82 is pivotally secured to the shaft 80 as by a verticalrocking pin 84 which allows the jaw to accommodate itself to anyirregularities or protuberances that may be present on the sealed unit.A set screw 85 fixes the position of the shaft 80 relative to the block76.

Each pair of standards 64 has, between the lower ends thereof, athreaded sleeve 86 which engages a lead screw 88. The lead screwsassociated with the slots 56 in oppositely extending arms 54 are inregistry and are interconnected for common rotation by a coupling 90that extends through the shaft 44. The lead screw on one side of theshaft has a right hand thread, and the lead screw on the other side ofthe shaft has a left hand thread, so that when the lead screws areturned in one direction they will move the two sleeves 86 toward oneanother and when turned in the opposite direction will move said sleevesapart. The sleeves carry outwardly extending pins 91 that engage thesides of the standards 64 Whereby movement of the sleeves in eitherdirection is im 4 parted to the standards. The outer ends of the leadscrews are journalled in depending flanges 92 at the outer ends of thearms 54, each of said journals protruding from the flange and carrying across pin 94 to facilitate engagement with a crank handle 95.

It is apparent that when the lead screws are turned in one direction theclamping jaws 82 will move together, and when turned in the oppositedirection they will move apart. The clamping jaws are equidistant fromthe center of the hub 52 so that when both jaws firmly engage the casingof a sealed unit the center of said unit will be on a line perpendicularto the lines between the jaws and passing through the axis of the shaft44.

An identical arrangement is provided for the other pair of arms. Thus,when all four clamping jaws engage a casing it will be centered on theaxis of the shaft 44.

It will be observed that the coupling for the second pair of lead screwsis journalled in the shaft 44 below the coupling 90 (see Figs. 1 and 3).

It will be undenstood that for some casings it will be desirable to havethe jaws located higher than for other types of casings and it is forthis reason that vertical adjustment of the jaws is made available bythe pins 66 and apertures 68. It will be clear that it is not necessaryfor all the jaws, or even for the two jaws of an associated pair to liein the same horizontal plane inasmuch as the presence of irregularitieson the surface of the sealed unit casings may make it desirable to haveone jaw, or a pair of jaws, higher than the remaining jaws, and it isfor this reason that I have made the several jaws independentlyadjustable in height.

The casing of a sealed unit is supported on the table 50. To enable thesupport to be vertically adjustable, I employ a horizontal platform 96carried by a vertical threaded rod 98 which is secured in a verticallytapped bore 100 at the center of the table. By properly adjusting theheight of the platform, it usually is possible to so locate the unitthat all four jaws can be located in the same horizontal plane, or sothat at least the jaws of each pair of associated jaws, i. e.,oppositely facing pair of jaws, can be located in the same plane,whereby a firmer grip is obtained on a casing.

Power actuated means is provided to rotate the table 50 around thevertical axis of the shaft 44. Said means includes an electric motor 102(Figs. 1 and 2) whose output shaft 104 is connected to a gear reductionbox 106 having an output sprocket (not shown) which turns about avertical axis parallel to the axis of the shaft 44. A chain 108 trainedabout the output sprocket passes through an opening 109 in the column 42and engages a drive sprocket 110 fixed on the shaft 44 near its lowerendv Thus, as soon as the motor 102 is energized the table 50 will beslowly turned and the unit 26 revolved about a vertical axis passingthrough the center of the unit.

The grinding head 22 includes a grinding wheel 112, power actuated meansto rotate said wheel about an axis, means mounting said Wheel with itsaxis of rotation selectively lying in either a vertical or a horizontalplane depending upon the type of unit to be opened, means to adjust theheight of the wheel so as to match the height of the welded joint to beground, means supporting the wheel for shiftable movement toward andaway from the unit in a vertical direction when the axis of rotation ishorizontal and in a horizontal direction when the axis of rotation isvertical, and means biasing the wheel against the welded joint.

More specifically, the grinding wheel 112 is mounted on the drive shaft114 of an electric motor 116. The motor is carried by a cradle 118 whichis fastened to an end of a massive rocking shaft 120. Said shaft extendsthrough a sleeve 122, being journalled therein for either axial orrotary movement.

The sleeve is provided with vertical slots 124 (see Fig. 8) spacedinwardly from opposite ends thereof and extending from the top to thebottom of the sleeve on one side thereof. The other side of the sleeveis solid; In addition, the sleeve includes horizontal slots 126 runningfrom the center of each slot 124 to the adjacent end of the sleeve. Ithus provide at opposite ends of the sleeve spaced curved fingers 128,130 (see Fig. 7) which function as split collars selectively to engageor release the rocking shaft. The fingers can be urged together byscrews 131. When the screw-s are tightened the shaft will be firmlyheld; when the screws are loosened the shaft is released for eitherrotation or axial translation.

The rocking shaft has an axial extension 133 of reduced diameter onwhich a counterweight 132 is slidable, being held in any adjustedposition by a set screw 134.

The sleeve 122 includes a pair of oppositely extending horizontaltrunnions 136 (see Fig. 6) journalled in bearing blocks 138. The blocksare secured to a turnplate 149 that rests on a slip disc 142 seated on acapstan hub 144. The capstan barrel 146 is externally threaded forengagement with the threaded bore 148 of a ferrule 150 that isfriction-fitted in the upper end of a hollow vertical column 152. Theturnplate is steadied by a stay rod 154 whose upper end is fastened tothe center of said plate and whose lower end is secured in a bearing 158centrally disposed in the barrel 146. Thus the turnplate is able tomaintain a fixed angular orientation while the capstan is being turnedto vary the height of the trunnions 136.

Rotation of the capstan is facilitated by spokes 160.

A pair of horizontaly extending gibs 162 (see Figs. 1, 8 and 9) arecarried by a yoke 164 which is mounted on the upper end of the standard166 in such manner as to permit the height of the yoke to be adjusted.The standard is supported by a bracket 168 extending from a split collar170 that embraces the column 152. The gibs 162 are spaced apart toslidably receive the shaft 120 sidewise and thereby limit movement ofthe grinding wheel 112 to a horizontal plane, i. e. so that the wheelwhich is set to turn about a vertical axis will approach the weldedjoint in a horizontal direction.

A second bracket 172 is carried by the collar 170 or, if desired, by aseparate split collar on the column 152. Said second bracket supportsfor adjustable vertical movement a shaft 174 that carries a pair ofstandards 176 at its upper end. The shaft 174 is located in a positionspaced outwardly of the counterweight end of the shaft 120 and with thestandards at about the level of said shaft 120. The standards 176support a sheave 178 for rotation about a horizontal axis approximatelyparallel to the shaft 120 when the latter is in operative position.

A rope, chain, cable or similar flexible member 180 trained about thesheave 178 carries a biasing weight 182 at its lower end and is attachedat its upper end to a strap 184 clamped on the reduced diameter portion133 of the shaft 120.

In the operation of the device the two pairs of lead screws are turnedto move apart both opposed pairs of clamping jaws 82 and leave ampleroom for insertion therebetween of the unit 26 which is to be opened.The platform 96 is spun until it is at the proper height for support ofthe unit.

The unit is seated on the platform and one pair of lead screws turned tobring its jaws into engagement with the unit. Unless the unit happens tohave been centered accidentally by hand, one of the jaws will engage theunit before the other and push the unit into abutment against theassociated jaw so that the unit will be centered with respect to thepair of jaws being actuated. These jaws then are backed off slightlyfrom the unit and the other pair of jaws caused to engage the unit. Bothpairs of jaws thereupon are tightened on the unit whose laterallyextending welded joint 32 now is substantially centered about the axisof the revolution of the shaft 44.

It will be observed that if the unit is one in which the welded jointprotrudes laterally, the grinding wheel 112 must be disposed in ahorizontal plane for rotation about a vertical axis and said wheel mustbe shiftable in a horizontal plane to accommodate for irregularities inthe joint, to enable the wheel to follow joints of other than circularshape and to enable the wheel to bite into the joint. To set thegrinding head in such a manner the operator loosens the clamping screws131 and turns the shaft 120 until the axis of rotation of the grindingwheel 112 is vertical as shown in Fig. 1. In addition, he axially shiftsthe shaft until the distance from the grinding wheel to the center ofthe column 152 is about equal to or slightly less than the distance fromthe center of said column to the center of the shaft 44. The screws 131then are tightened.

With the gibs 162 disengaged from the shaft 120, the height of thetrunnions 136 is vertically adjusted by turning the capstan until saidshaft is substantially horizontal when the grinding wheel is in theplane of the welded joint. The height of the gibs 162 then is adjustedand said gibs are swung back to engage the shaft 120 and maintain thesame in a fixed horizontal plane as it rocks about the axis of thevertical stay rod 154. The counterweight is adjusted to substantiallycounterbalance the grinding wheel and motor so as to minimize frictionat the gibs.

It will be observed that as the capstan is rotated to raise or lower theturnplate, due to the relative angular movement permitted between saidplate and the capstan, the bearing blocks 138 and sleeve 122 canmaintain a fixed angular position with the grinding wheel against thewelded joint 32.

With the parts set in the foregoing manner, the motors 102, 116 areenergized so that the table will turn slowly as the grinding wheel spinsat a high speed. The horizontal plane of the welded joint remains fixed,and the grinding wheel under the influence of the gibs 162 will stay inthis plane, being biased against the unit by the weight 182. As the unitturns, if the seam should be shaped irregularly, it will push out thegrinding wheel which rocks about the stay rod 154 while remaining in theset horizontal plane.

If the machine is to grind down the welded joint 40 of a unit 34 inwhich the seam is located at the top (see Fig. 12) rather than the side,the grinding head must be reset so that the grinding wheel turns about ahorizontal axis and is shiftable vertically. For this setup the sealedunit 34 is inserted in the centering jig and clamped in position asheretofore described with respect to the unit 26. The screws 131 areloosened and the shaft 120 rotated to locate the axis of rotation of thegrinding wheel 112 horizontally. At the same time the shaft is axiallyshifted until the distance from the column 152 to the axis of rotationof the grinding wheel is about equal to the distance from said column tothe axis of the shaft 44. The capstan is adjusted until the shaft issubstantially horizontal when the grinding wheel is in contact with thewelded joint 40.

The machine 20 also includes means to confine the grinding wheel tomovement in a vertical plane at any selected distance from the axis ofthe shaft 44. Said means comprises a pair of spaced upright gibs 186extending from a yoke 188 (see Fig. 13) that is supported by avertically adjustable shaft 199 which is carried by the bracket 168 inlieu of the shaft 166. The collar 170 is loosened and the bracket 168rotated until the shaft 166 is directly below the shaft when thegrinding wheel is directly above the welded joint 40. The gibs 186 aredisposed to slidably receive the shaft 120 between them. Thus the shaftis permitted to rock about the horizontal axis of the trunnions 136while being confined to movement in a set vertical plane which isdetermined by the position of the gibs 186.

When power is supplied to the motors 102 and 116, the unit 34 willrotate with the grinding wheel directly above the circular welded joint40. As the seam turns it will remain directly beneath the grindingwheel, said wheel being held at the radius of the joint by the gibs 186.However, the gibs permit vertical rocking movement of the grinding wheelto accommodate for unevenness in the seam.

The counterweight 132 is so located along the reduced diameter portion130 of the shaft 120 that it is slightly overbalanced by the motor 116whereby the grinding wheel is biased against the welded joint.

In certain cases, as for example where the seam is difficult of access,it is advantageous to locate the plane of the wheel at an angle to boththe vertical and the horizontal. Furthermore, it is sometimesadvantageous to shift the wheel in a plane other than a vertical or ahorizontal plane; the universal mounting of the shaft 120 permits suchmotion. Usually it is desirable to shift the wheel in its own plane,that is to say, in a plane perpendicular to its axis of rotation.

It thus will be seen that there is provided an apparatus which achievesthe several objects of the invention and is well adapted to meet theconditions of practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment above set forth,it is to be understood that all matter herein described, or shown in theaccompanying drawings, is to be interpreted as illustrative and not in alimiting sense.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

1. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga table, means to mount said table for rotation about an axis, poweractuated means for slowly turning said table about said axis, acentering jig carried by said table for clamping a unit thereon with thewelded joint centered on the axis of rotation of the table, saidgrinding head including a grinding wheel, power actuated means forrotating said wheel about an axis, means mounting said wheel with itsaxis of rotation selectively lying in a plane which is variable fromvertical to horizontal, means supporting and guiding the wheel forshiftable floating movement toward and away from the unit in anyselected plane from vertical to horizontal, means to adjust the heightof the wheel, and means to bias the wheel against the welded joint forapplying a yielding operative pressure against the welded joint.

2. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga table,

means to secure a unit to the table, means to mount said table forrotation about an axis, power actuated means for slowly turning saidtable about said axis, said grinding head including a grinding wheel,power actuated means for rotating said wheel about an axis, meansmounting said wheel with its axis of rotation selectively lying in aplane which is variable from vertical to horizontal, means supportingand guiding the wheel for shiftable floating movement toward and awayfrom the unit in a plane which is perpendicular to the axis of rotationof the wheel, means to adjust the relative position of the table andwheel to match the height of the wheel to the height of the weldedjoint, and means to bias the wheel against the welded joint for applyinga yielding operative pressure against the welded joint.

3. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga horizontal table, means to secure a unit to the table, means to mountsaid table for rotation about a vertical axis, power actuated means forslowly turning said table about said axis, said grinding head includinga grinding wheel, power actuated means for rotating said wheel about anaxis, means mounting said Wheel with its axis of rotation selectivelylying in either a vertical or a horizontal plane, means supporting andguiding the wheel for shiftable floating movement toward and away fromthe unit in a vertical direction when the axis of rotation is horizontaland in a horizontal direction when the axis of rotation is vertical,means to adjust the relative position of the table and wheel to matchthe height of the wheel to the height of the welded joint, and means tobias the wheel against the welded joint for applying a yieldingoperative pressure against the welded joint.

4. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga table, means to secure a unit to the table, means to mount said tablefor rotation about an axis, power actuated means for slowly turning saidtable about said axis, said grind; ing head including a grinding Wheel,power actuated means for rotating said wheel about an axis, meansmounting said wheel with the axis of rotation selectively lying in aplane which is variable from vertical to horizontal, means supportingand guiding the wheel for shiftable floating movement toward and awayfrom the unit in any selectable plane from vertical to horizontal, meansto adjust the relative position of the table and wheel to match theheight of the wheel to the height of the welded joint, and means to biasthe wheel against the welded joint for applying a yielding operativepressure against the welded joint.

5. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga horizontal table, means to mount said table for rotation about avertical axis, power actuated means for slowly turning said table aboutsaid axis, means carried by said table for clamping a unit thereon withthe welded joint centered on the axis of rotation of the table, saidgrinding head including a grinding wheel, power actuated means forrotating said wheel about an axis, means mounting said wheel with itsaxis of rotation selectively lying in either a vertical or a horizontalplane, means supporting and guiding the wheel for shiftable floatingmovement toward and away from the unit in a plane perpendicular to theaxis of rotation of the wheel, means to adjust the relative position ofthe table and wheel to match the height of the wheel to the height ofthe welded joint, and means to bias the wheel against the welded jointfor applying a yielding operative pressure against the welded joint.

6. A grinder as set forth in claim 5 wherein means is providedselectively to confine the grinding wheel for shiftable floatingmovement in a vertical direction or a horizontal direction.

7. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga horizontal table, means to mount said table for rotation about avertical axis, power actuated means for slowly turning said table aboutsaid axis, means carried by said table for clamping a unit thereon withthe welded joint centered on the axis of rotation of the table, saidgrinding head including a grinding wheel, power actuated means forrotating said wheel about an axis, means mounting said wheel with itsaxis of rotation selectively lying in either a vertical or a horizontalplane, a universal joint supporting the wheel for shiftable movementtoward and away from the unit, means to bias the wheel against thewelded joint for applying a yielding operative pressure against thewelded joint, and means selectively confining the wheel for shiftablefloating movement in any selected direction.

8. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga horizontal table, means to mount said table for rotation about avertical axis, power actuated means for slowly turning said table aboutsaid axis, mean-s carried by said table for clamping a unit thereon withthe welded joint centered on the axis of rotation of the table, saidgrinding head including a grinding wheel, power actuated means forrotating said wheel about an axis, means mounting said wheel with itsaxis of rotation selectively lying in any plane from vertical tohorizontal, a substantially horizontal shaft supporting the wheel, meansmounting the shaft for rotation about vertical and horizontal axesspaced from the axis of rotation of the wheel, means confining the shaftselectively for shiftable floating movement in any direction, means toadjust the height of the wheel to match the height of the welded joint,and means to bias the wheel against the welded joint for applying ayielding operative pressure against the welded joint.

9. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga table, means to mount said table for rotation about an axis, poweractuated means for slowly turning said table about said axis, meanscarried by said table for clamping a unit thereon with the welded jointcentered on the axis of rotation of the table, said grinding headincluding a grinding wheel, power actuated means for rotating said wheelabout an axis, means mounting said wheel with its axis of rotationselectively lying in a plane which is variable from vertical tohorizontal, means supporting the wheel for rocking floating movementtoward and away from the unit in any selected plane from vertical tohorizontal, means independent of the foregoing means to vary thedistance from the grinder to the axis of rotation of said table, meansto adjust the height of the wheel, and means to bias the wheel againstthe welded joint for applying a yielding operative pressure against thewelded joint.

10. In a grinder for opening a hermetically sealed unithaving a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga horizontal table, means to mount said table for rotation about avertical axis, power actuated means for slowly turning said table aboutsaid axis, means carried by said table for clamping a unit thereon withthe welded joint centered on the axis of rotation of the table, saidgrinding head including a grinding wheel, power actuated means forrotating said wheel about an axis, a substantially horizontal shaft,means mounting the wheel on the shaft with the axis of rotation of thewheel perpendicular to the longitudinal axis of the shaft, a bearing inwhich the shaft is rotatable and translatable, means releasably lockingthe shaft with respect to the bearing, means mounting the shaft forrotation about vertical and horizontal axes, means selectively confiningthe shaft for rocking floating movement in a vertical or horizontalplane, means to adjust the height of the wheel to match the height ofthe welded joint, and means to bias the wheel against the welded jointfor applying a yielding operative pressure against the welded joint.

11. A grinder as set forth in claim wherein the means for selectivelyconfining the shaft for floating movement in a vertical or a horizontalplane comprises horizontal gibs and vertical gibs selectively engagingthe shaft, vertically adjustable means supporting the horizontal gibs,and means supporting the vertical gib-s at an adjustable angle withrespect to the vertical axis of rotation to the shaft.

12. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane and located at the side of the casing, a grinding head and awork holder, said work holder comprising a horizontal table, means tomount said table for rotation about a vertical axis, power actuatedmeans for slowly turning said table about said axis, means carried bysaid tab-1e for clamping a unit thereon with the welded joint centeredon the axis of rotation of the table, said grinding head including agrinding Wheel, power actuated means for rotating said wheel about avertical axis, means supporting and guiding the wheel for shiftablefloating movement toward and away from the unit in a horizontaldirection, means adjustably supporting the wheel at a height matchingthe height of a welded joint, means biasing the wheel against the weldedjoint for applying a yielding operative pressure against the Weldedjoint, and means independent of the foregoing means for selectivelyvarying the distance from the wheel to the axis of rotation of thetable.

13. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by anendless welded joint lying in aplane and located at the top of the casing, a grinding head and a workholder, said work holder comprising a horizontal table, means to mountsaid table for rotation about a vertical axis, power actuated means forslowly turning said table about said axis, means carried by said tablefor clamping a unit thereon with the welded joint centered on the axisof rotation of the table, said grinding head including a grinding wheel,power actuated means for rotating said wheel about a horizontal axis,means supporting and guiding the wheel for shiftable floating movementtoward and away from the unit in a vertical direction, means adjustablysupporting the wheel at a height matching the height of a welded joint,means biasing the Wheel against the welded joint for applying a yieldingoperative pressure against the welded joint, and means independent ofthe foregoing means for selectively varying the distance from the wheelto the axis of rotation of the table.

14. In a grinder for opening a hermetically sealed unit having a casingincluding at least two parts joined by an endless welded joint lying ina plane, a grinding head and a work holder, said work holder comprisinga horizontal table, means to mount said table for rotation about avertical axis, power actuated means for slowly turning said table aboutsaid axis, a centering jig including plural pairs of clamps ofindividually adjustable heights carried by said table for clamping aunit thereon with the welded joint centered on the axis of rotation ofthe table, said grinding head including a grinding wheel, power actuatedmeans for rotating said wheel about an axis, means mounting said wheelwith its axis of rotation selectively lying in a plane which is variablefrom vertical to hori-' zontal, means supporting and guiding the wheelfor rocking floating movement toward and away from the unit in anyselected plane from vertical to horizontal, means to adjust the heightof the wheel, and means to bias the wheel against the welded joint forapplying a yielding operative pressure against the welded joint.

References Cited in the file of this patent UNITED STATES PATENTS455,195 Fulmer et al June 30, 1891 540,499 Koegel June 4, 1895 985,412Hattersley et a1 Feb. 28, 1911 1,340,409 Rude May 18, 1920 2,142,710Bigelow Jan. 3, 1939 2,587,952 Appleby Mar. 4, 1952 FOREIGN PATENTS125,534 Switzerland Apr. 16, 1928 517,985 Germany Jan. 22, 1931

